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RE: BOLT TORQUE/TENSION RELATIONSHIP

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Harold Sprague, I thank you for gentle response to my
question, Jim J
--- "Sprague, Harold O." <SpragueHO(--nospam--at)bv.com> wrote:
> Jim, 
> A hydraulic tensioner is a device which attaches to
> the threads beyond the
> nut.  It applies a tension load on directly on the
> bolt.  The nut is then
> turned to lock in the tension.  The nuclear and
> petrochemical industries
> have used these for many years to apply a specific
> tension load on a bolt.
> Check out:
> http://www.htico.com/vmspec-index.htm
> http://www.biach.com/Home/home.html
> http://www.tentec.net/
> 
> You can also use a calibrated load indicating
> washer:
> http://www.turnasure.com/index.htm
> 
> You can still just use 2 wrenches to tighten a bolt.
>  The turn of the nut
> method is what I first learned as an iron worker
> shortly after dirt was
> invented.  The trick is to use match marking with a
> paint stick.  It saves a
> lot of heart ache after a rain storm hits washing
> off all of the chalk marks
> and you don't know how to inspect a bolt
> installation.  
> 
> Torque wrenches CAN work reasonably well inside a
> machine manufacturing
> facility where all of the bolts have no burrs, have
> no corrosion, and have a
> nice coating of lubricant.  But even there, if you
> take a sampling of bolts
> with varying lubricants, burring, and surface
> conditions and load them into
> a Skidmore, you will see that tension in bolts will
> not be all that
> consistent.
> 
> Regards,
> Harold O. Sprague
> 
> -----Original Message-----
> From: jim jensen [mailto:doublejtp(--nospam--at)yahoo.com] 
> Sent: Friday, July 11, 2003 12:09 AM
> To: seaint(--nospam--at)seaint.org
> Subject: RE: BOLT TORQUE/TENSION RELATIONSHIP
> 
> 
> Please to tell me, just what is a "Hydraulilc
> Tensioner" and how does one go about using them in
> the field??,interesting
> info on this Board, of which, just how does one go
> about "tighening" a bolt,
> if a person, just plain cannot use two wrenches.
> I'am  also curious as to
> what applications this needs to be so seriously
> addressed. I thank you, Jim
> Jensen, just a residential builder.
> --- "Sprague, Harold O." <SpragueHO(--nospam--at)bv.com> wrote:
> > I think that Charlie Carter's morning cup of
> coffee
> > has kicked in now enough
> > for spell check to work, but his point is correct.
> > The front of the AISC
> > "Specification for Structural Joints Using ASTM
> A325
> > or A490 Bolts" states
> > that it was prepared by RCSC Committee 15.  The
> > recommendations by AISC are
> > the same as the RCSC.  
> > 
> > Aside from Charlie's spell check lapse, there are
> 4
> > methods listed in the
> > RCSC that are intended to "pretension" a bolt. 
> None
> > of them will allow you
> > to just use a torque wrench and pretension bolts.
> > The closest thing is the
> > Calibrated Wrench in Sec. 8.2.2.  It states that
> > "... Torque values
> > determined from tables or from equations that
> claim
> > to relate torque to
> > pretension without verification shall not be
> used." 
> > The commentary is also
> > a good read when it comes to this topic.  Frankly
> > the effort to properly
> > install and inspect bolts using the Calibrated
> > Wrench method are so
> > difficult, I don't allow it in the specifications
> > that I write, and I can't
> > even recall a project in the last 20 years in
> which
> > Calibrated Wrench was
> > used.  
> > 
> > The torque wrench is allowed ONLY as a means of
> > arbitration.  The torque
> > wrench is NOT allowed as a method of 
> installation,
> > nor is it allowed for
> > inspection.
> > 
> > The goal is to provide a pretension in the bolt
> per
> > RCSC Table 8.1.  Torque
> > is irrelevant. Now with all of that, I must
> confess
> > that I have used torque
> > as a method to provide a pretension force on some
> > anchor bolts.  But I was
> > conservative, it was not all that critical of an
> > application, and I required
> > some serious inspection.  On critical anchor
> bolts,
> > I require hydraulic
> > tensioners.
> > 
> > Regards,
> > Harold O. Sprague
> > 
> > 
> > -----Original Message-----
> > From: Christopher Wright
> > [mailto:chrisw(--nospam--at)skypoint.com]
> > Sent: Wednesday, July 09, 2003 11:37 PM
> > To: ?
> > Subject: RE: BOLT TORQUE/TENSION RELATIONSHIP
> > 
> > 
> > >Torquing bolts is not an accepted method of bolt
> > pretensioning by the
> > >RCSC. The only "torque" method discussed in the
> > RCSC is for arbitration
> > >ONLY.
> > Why do you suppose RCSC takes this position so
> much
> > different than that
> > taken by the AISC? Have safety issues been
> > uncovered, using the AISC 
> > calibrated wrench or turn-of-the-nut methods been
> > founf defective?
> > 
> > Christopher Wright P.E.    |"They couldn't hit an
> > elephant at
> > chrisw(--nospam--at)skypoint.com        | this distance"  
> (last
> > words of Gen.
> > ___________________________| John Sedgwick,
> > Spotsylvania 1864)
> > http://www.skypoint.com/~chrisw
> > 
> > 
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